Control of initiation of viral plus strand DNA synthesis by HIV reverse transcriptase.
Human immunodeficiency virus reverse transcribes its single-stranded RNA genome making a DNA copy. As synthesis proceeds, the RNA is simultaneously degraded to oligomers; one of these, the polypurine tract, primes synthesis of a plus strand DNA. The viral reverse transcriptase (RT) degrades all of the non-polypurine tract oligomers. We show that unlike other DNA polymerases the retroviral RT can bind either end of an annealed RNA primer, the 5'-end for degradation and the 3'-end for synthesis. The competition between the two binding modes at any primer determines whether it will be extended or degraded. The 5'-end binding can be suppressed in at least two ways. The sequence of the primer can be such that a region at the 5'-end is unannealed or a DNA primer can be annealed just adjacent to the 5'-end of the RNA primer. This promotes binding of RT to the RNA 3'-end, allowing a primer that would normally be degraded to be extended. Implications for human immunodeficiency virus replication and antiviral therapy are discussed.
Palaniappan
C
C
Department of Biochemistry & Biophysics, University of Rochester, Rochester, New York 14642, USA.
Kim
J K
JK
Wisniewski
M
M
Fay
P J
PJ
Bambara
R A
RA
D001665:Binding Sites; D004247:DNA / Q000096:biosynthesis*; D017931:DNA Primers / Q000235:genetics; D006678:HIV / Q000201:enzymology*; D006801:Humans; D009693:Nucleic Acid Hybridization / Q000235:genetics; D012313:RNA / Q000737:chemistry / Q000235:genetics; D012367:RNA, Viral / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D016914:Ribonuclease H / Q000235:genetics / Q000378:metabolism
D017931:DNA Primers; C034477:RNA primers; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D012313:RNA; D004247:DNA; D012194:RNA-Directed DNA Polymerase; D016914:Ribonuclease H